Two-stroke fuel / oil mix calculator
How much petrol or gasoline do you have, and what petrol:oil ratio does your equipment specify? Calculate the oil to add, or start from measured oil or a desired final mixture.
Petrol quantity and final mixture are different
For an example 50:1 petrol:oil ratio, 5 L of petrol needs 100 mL of oil and makes approximately 5.1 L of mixture. To make 5 L of final mixture instead, use approximately 4.902 L petrol and 98.04 mL oil. Starting with 100 mL oil requires 5 L petrol. These examples illustrate the arithmetic; choose the ratio specified by your exact equipment manual.
The calculator uses volume ratios and assumes additive volumes for the final mixture. It does not select fuel suitability, oil compatibility or mixing order. US and Imperial gallons and fluid ounces have different sizes; the displayed unit system always remains explicit.
Example reference amounts at 50:1 petrol:oil
Oil added to measured petrol, rather than quantities for a final batch. This is an example ratio, not an equipment default.
| Petrol already measured | Oil to add |
|---|---|
| 1 L | 20 mL |
| 2 L | 40 mL |
| 5 L | 100 mL |
| 10 L | 200 mL |
| 1 US gal | 2.56 US fl oz |
| 1 Imperial gal | 3.2 Imperial fl oz |
Checked manufacturer reference
STIHL USA: mixing oil and gasoline describes gasoline-to-two-cycle-oil ratios and tells readers to consult the equipment manual. Reviewed 4 October 2026. Its rounded US reference chart does not replace exact unit conversion here. This calculator also accepts other explicitly supplied ratios; the reference does not establish a universal ratio for other manufacturers or equipment.
Two-stroke, 2-stroke and 2-cycle refer to the mixing task covered here. Follow the exact equipment manual for fuel and oil specifications, mixing and safe handling.
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